shuang_astronomyfandomcom-20200214-history
ArXiv ExgCo
Early-Type Galaxies * Galaxy Group and Cluster * Star Forming in Galaxies * Active Galactic Nuclei * Really High-Redshift Universe * The Large-Scale Structure and Cosmology Early Type Galaxies * There is some strong evidence that giant elliptical galaxies grow their extended stellar haloes slowly, through accretion, around a dense, compact core (e.g. van Dokkum et al., 2010; van Dokkum & Conroy, 2012) arXiv:1212.1451 Extragalactic Globular Clusters * GCs around isolated elliptical galaxies: arXiv:1212.1451 *# NGC 720 (Kissler-Patig et al. 1996) *# NGC 821 (Spitler et al. 2008) *# NGC 3585 (Hempel et al. 2007; Humphrey et al. 2009; Lane et al. 2012) *# NGC 3818 (Cho et al. 2012) *# NGC 5812 (Lane et al. 2012) * In many cases it seems that red (metal rich) GC populations may have formed in situ along with the galaxy, while the bluer (more metal poor) GCs arrived later as part of the hierarchical merger process, assuming mainly minor mergers (Lee et al., 2008; Elmegreen et al., 2012) arXiv:1212.1451 * The Washington photometric system (Canterna, 1976) has been chosen as it has the advantage of being a good discriminator between compact blue background galaxies and GC candidates (Dirsch et al., 2003a); Furthermore, an apparently Universal peak exists in the (C−R) colour of old globular cluster populations associated with elliptical galaxies (e.g. Richtler et al., 2012) arXiv:1212.1451 Intra-Cluster Light * The importance of the ICL in the baryon budget is the subject of current debate: arXiv:1212.1613 *# Krick & Bernstein 2007: 6-22% within 25% of Virial radius *# Gonzalez et al. 2005; 2007: 33% for BCG+ICL within $r_200$ *# McGee & Balogh 2010: ~50% (mapping of hostless SN Ia) *# Zibetti et al. 2005: ~11% within 500kpc (stacking of SDSS cluster) High-Redshift Early-Type Galaxies * The quiescent galaxies form a signiﬁcant fraction (30 − 50%) of all massive z~2 galaxies (e.g. Kriek et al. 2006; Williams et al. 2009; Toft et al. 2009) arXiv:1212.1158 Galaxy Group and Cluster * First evidence of superclusters as agglomerations of rich clusters of galaxies: Abell 1961 arXiv:1212.1597 ** Superclusters are generally deﬁned as groups of two or more galaxy clusters above a given spatial density enhancement (Bahcall 1988) ** The existence of superclusters was confirmed by: Bogart & Wagoner 1973; Hauser & Peebles 1973; Peebles 1974 ** Catalogs of superclusters: e.g. Rood (1976), Thuan (1980), Bahcall (1984), Batuski & Burns (1985), West (1989), Zucca et al. (1993), Kalinkov & Kuneva (1995), Einasto et al. (1994, 1997, 2001, 2007), and Liivamagi et al. (2012) * The Dressler-Shectman test for substructure in galaxy cluster : (Dressler & Shectman 1988; Halliday et al. 2004) ** {\delta}^2=\frac{11} )^2+({\sigma}_{loc}-{\sigma}_v)^2] ** {\overline{v}} and {\sigma}_v is the mean velocity and velocity dispersion of the cluster. ** v_{loc} and {\sigma}_{loc} } is the mean velocity and velocity dispersion of that galaxy and its ten nearest neighbours within the cluster ** The sum of the \delta value of each galaxy, /Delta , gives the measure of the total substructure present in a cluster. * Coincidence between cool X-ray emitting gas and Ha filaments: *# ESO 137-001 in Abell 3627: (Sun et al. 2007 ) *# BCG of Perseus Cluster: (Sanders & Fabian 2007; Fabian et al. 2008, 2011 ) *# BCG of Centaurus Cluster: (Sanders & Fabian 2002, 2008 ) *# Virgo: M87 (Werner et al. 2010, 2012 ); M86 (Ehlert et al. 2012) Environmental Effect on Stars and Gas # '''Ram-pressure Stripping: (Gunn & Gott ) #* Complex physics is required to account for the morphology of the stripped gas tails and their multiwavelength properties (e.g. Roediger & Bruggen 2006, 2007, 2008b; Tonnesen & Bryan 2010; Tonnesen et al. 2011; Tonnesen & Bryan 2012 ) # Viscosity of the ICM: (Roediger & Bruggen 2008a ) # Turbulence and Magnetic Fields: (Ruszkowski et al. 2012 ) Dwarf Galaxies Blue Compact Dwarf Galaxies * Nearby blue compact dwarf galaxies (BCDs) are a unique category of galaxies that have low metallicity and high gas fraction in the nearby Universe (Sargent & Searle 1970; van Zee, Skillman, & Salzer 1998; Kunth & Ostlin 2000 ) **Some BCDs are also experiencing the most active class of star formation with the formation of super star clusters (SSCs) (Turner et al. 1998; Kobulnicky & Johnson 1999 ). ** All these BCDs are also classiﬁed as Wolf-Rayet galaxies: the Wolf-Rayet feature indicates that the typical age of the current starburst is a few Myr (Vacca & Conti 1992; Lopez-Sanchez & Esteban 2010 ) Star Formation in Galaxies The X_CO Factor * A variety of observations have shown that \alpha\sim4.4 M_{\odot}{pc}^{-2} (K km s^{-1})^{-1} is characteristic of the local area of the Milky Way (Solomon et al. 1987; Strong & Mattox 1996; Abdo et al. 2010) arXiv:1212.1208 * Different techniques to explore the possibility of a changing X_CO across different types of galaxies in nearby Universe: *# These include virial mass measurements of individual GMCs in the Milky Way, the local group, and nearby spirals (e.g. Wilson 1995; Blitz et al. 2007; Bolatto et al. 2008; Fukui & Kawamura 2010, and references therein) *# Estimating the molecular gas mass from dust far-IR emission modeling while constraining the dust-to-gas ratio and the contribution from atomic hydrogen (Israel 1997; Leroy et al. 2011, 2012) *# Using the star formation rate (SFR) under the assumption of a known molecular gas depletion timescale to estimate the amount of H_2 (Schruba et al. 2012; McQuinn et al. 2012). ** X_CO shows higher values for lower metallicity systems. This increase is most likely driven not only by a decrease in the carbon and oxygen abundances, but mainly by a drop in the optical depth within GMCs due to a lower abundance of dust. The CO/C+ dissociation boundary moving inwards within the clouds, leaving behind large envelopes of "CO Dark" molecular gas (e.g Bolatto et al. 1999) ** The molecular gas in merging and starburst galaxies show X_CO value factors of a few lower than the MW value. (Wild et al. 1992; Shier et al. 1994; Mauersberger et al. 1996; Solomon et al. 1997; Downes & Solomon 1998; Bryant & Scoville 1999; Meier et al. 2010) *** This eﬀect is thought to be caused by the impact of higher gas temperatures and stronger turbulence on the brightness temperature of the CO line and the escape probability of CO(1-0) photons. (Shetty et al. 2011) *** The lower X_CO factor is also found in high-redshift "normal" star-forming galaxies (Genzel et al. 2012) arXiv:1212.4152 * A series of studies using analytic models, numerical simulations, and combinations of both, have examined the dependance of X_CO with metallicity, gas temperature, gas dynamics, and the local radiation ﬁeld (e.g. Krumholz et al. 2011; Shetty et al. 2011; Narayanan et al. 2012; Feldmann et al. 2012a) arXiv:1212.4152 * The value of X_CO has been shown to change as a function of galactocentric radius in the MW using a series of diﬀerent techniques: *# Dust emission modeling (Sodroski et al. 1995) *# Measurements of gamma-ray emissivity from cosmic-ray gas interactions (Digel et al. 1996; Strong et al. 2004; Abdo et al. 2010) *# Direct virial mass measurements of GMCs (Arimoto et al. 1996; Oka et al. 1998). arXiv:1212.4152 Star Formation Rate Calibration and Star-Formation Law * Schimdt-Kennicutt law (Schmidt 1959; Kenicutt 1998) ** studies of this law in spatially resolved manner across the disk of nearby galaxies (Kennicutt et al. 2007; Bigiel et al. 2008; Blanc et al. 2009; Verley et al. 2010; Onodera et al. 2010; Schruba et al. 2011; Liu et al. 2011; Rahman et al. 2012) *** About the uncertainty in the slope: (Blanc et al. 2009; Rahman et al. 2012; Calzetti et al. 2012) *** The normalization is consistent with a depletion timescale for molecular gas of ~ 2Gyr at the typical molecular gas surface densities (Leroy et al. 2008; Rahman et al. 2012) * Radio-FIR Correlation: (de Jong et al. 1985; Helou, Soifer & Rowan-Robinson 1985) Active Galactic Nuclei Black Hole Mass Estimation * The black hole mass is usually estimated using reverberation mapping calibrated scaling relations (the so–called “single epoch virial method”, or SE virial, Peterson 1993; Peterson et al. 2004; Onken et al. 2004; Vestergaard & Peterson 2006; Bentz et al. 2009). arXiv:1212.1181 Relation and Coevolution with Host Galaxy * Correlations between the mass of the central black hole and absolute magnitude (Magorrian et al. 1998; Marconi & Hunt 2003; Häring & Rix 2004 ), and/or stellar velocity dispersion (Gebhardt et al. 2000; Merritt & Ferrarese 2001 ) of the spheroidal component indicate that the mass ratio between a SMBH and its bulge is constant over a wide dynamic range in mass (0.0014) arXiv:1212.2999 * Related Measurements: ** Optical imaging from space with HST can be used to disentangle the light between an AGN and its host galaxy (e.g., Sánchez et al. 2004; Jahnke et al. 2004, 2009; Bennert et al. 2011b; Cisternas et al. 2011 ) ** Measure the stellar velocity dispersion from optical spectra for less luminous AGNs (Woo et al. 2008 ) ** Measure the stellar mass' content of AGN host galaxies through template ﬁtting of the broad-band photometric spectral energy distribution (Merloni et al. 2010; Brusa et al. 2009; Xue et al. 2010 ) ** Bulge luminosity from decomposition (Giavalisco et al. 2004) ** Possible biases originating from selection of AGN (see '' Salviander et al.2007; Lauer et al. 2007'' ) * Offsets from local M_{BH}-M_{Bulge} relation: (see Peng et al. 2006a, b ) ** Evidence for elevated black hole masses as compared to either the bulge component (Woo et al. 2008; Bennert et al. 2011b) or total (Merloni et al. 2010 ) stellar mass of the host galaxy. ** Undermassive bulge ? (Jahnke et al. 2009; Cisternas et al. 2011 ) Torus, BLR, Nuclear Gas et al. *By means of Adaptive Optics (AO) integral-ﬁeld spectroscopy, Hicks et al. (2009, hereafter H09) showed that the molecular gas in the central tens of parsecs of Seyfert galaxies relates directly to the largest structures associated with the obscuring torus, as predicted by clumpy torus models (e.g., Nenkova et al. 2002, 2008; Schartmann et al. 2008): it is in a rotating disk-like distribution, has a high velocity dispersion relative to rotation (V/σ<1), and is optically thick arXiv:1212.1162 *HCN measurements of Seyfert galaxies suggest that the nuclear dense gas also has a large dispersion (Sani et al. 2012) arXiv:1212.1162 Observed Spectral Properties * The X-ray/UV ratio (alpha_ox) is found to be strongly anti-correlated with the ultraviolet specific luminosity L_{UV} . (Strateva et al. 2005; Steen et al. 2006; Just et al. 2007; Gibson et al. 2008; Grupe et al. 2010; Vagnetti et al. 2010 ) ** About its dispersion, "artiﬁcial alpha_ox variability" due to non-simultaneity is not the main cause of dispersion (Vagnetti et al. 2010) arXiv:1212.3432 'Bumps' in AGN SED # Big Blue Bump: (BBB: 3000-10000\AA; Sanders et al. 1989; Elvis et al. 1994; Richards et al. 2006) #* Thought to be the thermal radiation from accretion disk # Infrared Bump: (~10000\AA), accounts for 20-40% of the bolometric luminosity; #* Thought to be the thermal radiation emitted from a dusty torus located a~1 pc from the black hole (Sanders et al. 1989) # Small Blue Bump: (SBB: 2200-4000\AA); minor component that superimpose to the BBB #* is likely the blending of several iron lines and hydrogen Balmer continuum (Wills et al. 1985; Vanden Berk et al. 2001) # Synchrotron Bump: for radio loud AGN or powerful blazer, extending from radio to IR/optical wavelengths # Compton Bump: for powerful blazer, extending from X–rays to TeV energies Observations of Galaxy Evolution Star-Forming and AGN * The star formation rate density of the Universe peaks from z~1−3 (e.g., Bouwens et al. 2009; Magnelli et al. 2011; Murphy et al. 2011 ), an epoch in which the black holes within the center of massive galaxies are simultaneously building up their mass (Wall et al. 2005; Kelly et al. 2010 )arXiv:1212.2971 * X-ray is efficient in identifying AGN from z=1-3 (e.g. Alexander et al. 2003; Brandt et al. 2001; Giacconi et al. 2002 ) ** X-ray spectra show majority of sources are obscured by gas and dust (see review by Brandt & Hasinger 2005 ) * Based on the presence of polycyclic aromatic hydrocarbons and continuum thermal dust emission, mid-infrared spectra can be decomposed into the relative contributions of SF and AGN activity (e.g., Laurent et al. 2000; Armus et al. 2007; Sajina et al. 2007; Pope et al. 2008; Kirkpatrick et al. 2012a ). *# At NIR: SF galaxy has a 1.6 micron bump from old population; AGN is pure power-law *# Dust temperature from FIR peak and shape: more warmer for more luminous AGN (Haas et al. 2003) IGM and CGM * Observed correlation between absorption lines in background quasars and the projected distance (and velocity offset) to the associated galaxy: ** Low-Redshift ': ''Chen et al. 2001; Chen & Tinker 2008; Thom & Chen 2008; Yao et al. 2008; Chen et al. 2010; Prochaska et al. 2011; Thom et al. 2011; Tumlinson et al. 2011 ** '''High-Redshift: Simcoe et al. 2004; Steidel et al. 2010 Galaxy Formation Theory Models v.s Observations * Cooling Crisis: Gas cools radiatively during the hierarchical buildup of the halo population and condenses to form galaxies in halo cores, results in more massive galaxies than observed (Balogh et al. 2001; Lin & Mohr 2004; Tornatore et al. 2003 ) ** Additional source of non-gravitational heating to prevent a cooling crisis (White & Rees 1978; Cole 1991; White & Frenk 1991; Blanchard et al. 1992 ) ** Stellar feedback seems not enough (Borgani et al. 2004 ) ** People started considering AGN feedback (Churazov et al. 2002; Springel et al. 2005a; McNamara & Nulsen 2007 ) *** Which resulted in the improvement on: ***# luminosity-temperature relation of X-ray clusters (Valageas & Silk 1999; Bower et al. 2001; Cavaliere et al. 2002 ) ***# luminosity function of galaxies (Croton et al. 2006; Bower et al. 2006; Somerville et al. 2008 ) arXiv:1212.4131 Inter-Stellar Medium * HI has long been the best tracer of Dark Matter (DM) in galaxies (e.g. Bosma 1981; van der Hulst et al. 1993). ** Typically the projected DM surface density scales very well with the measured HI surface density (Bosma 1981; Sancisi 1983; Carignan & Beaulieu 1989; Carignan et al. 1990; Carignan & Puche 1990a,b; Jobin & Carignan 1990; Broeils 1992; Meurer et al. 1996; Hoekstra et al. 2001). arXiv:1212.1502 IGM and CGM * Cold and hot-mode accretion (e.g. Binney 1977; Birnboim & Dekel 2003; Keres et al. 2005; Ocvirk et al. 2008; Keres et al. 2009; Faucher-Giguere et al. 2011; Van De Voort et al. 2011 ) ** Observational identification of these cold stream could be hard due to low covering facter (3%-10% at z~2) (e.g Faucher-Giguere et al. 2011; Kimm et al. 2011 ) ** The cold streams at high-redshift contribute significantly to the observed population of Lyman-limit systems (Fumagalli et al. 2011 ) Magnetic Field in Galaxies * In galaxies, magnetic fields are suspected to be particularly important as here the magnetic pressure in the inter-stellar medium (ISM) becomes comparable to the thermal pressure. Magnetic fields may hence be dynamically relevant for the evolution of galaxies (Beck 2009) arXiv:1212.1452 * The structure and strength of magnetic fields in galaxies determines the propagation of cosmic rays (Strong & Moskalenko 1998; Narayan & Medvedev 2001) * Magnetic field strengths have been measured for a number of galaxies using: *# Zeeman splitting in maser emission (Robishaw et al. 2008) *# Radio Polarization measurements (Beck 2007) * The formation and amplification of magnetic field during galaxy formation (For recent review: Kulsrud & Zweibel 2008) ** Weak initial magnetic field could be cosmological origin, or were created by Biermann batteries. ** Further amplification can then proceed through: **# Structure formation flows (Dolag et al. 1999) **# Galactic Dynamo (Hanasz et al. 2004) **# Turbulent amplification (Arshakian et al. 2009) Extragalactic Background Light * The extragalactic background light (EBL), the diffuse, isotropic background radiation from far-infrared (FIR) to ultraviolet (UV) wavelengths, is believed to be predominantly composed of the light from stars and dust integrated over the entire history of the Universe (see Dwek & Krennrich 2012, for reviews). arXiv:1212.1683 ** The observed spectrum of the local EBL at z = 0 has two peaks of comparable energy density. The ﬁrst peak in the optical to the near-infrared (NIR) is attributed to direct starlight, while the second peak in the FIR is attributed to emission from dust that absorbs and reprocesses the starlight. ** Measurements of EBL zt z~0 in optical and NIR is hampered by zodiacal light (Hauser & Dwek 2001); but see Matsuoka et al. 2011 for measurement from Pioneer 10/11. ** Integration over galaxy number counts provide a ﬁrm lower bound on the EBL, and the observed trend of the counts with magnitude indicates that the EBL at z = 0 has been largely resolved into discrete sources in the optical/NIR bands (e.g. Madau & Pozzetti 2000; Totani et al. 2001; Keenan et al. 2010) ** The EBL can also be probed indirectly through observation of high-energy gamma rays from extragalactic objects (Mazin & Raue 2007) *** Observations of blazars by current ground-based telescopes have been able to place relatively robust upper limits to the EBL at z=0 and up to z~0.5 (e.g. Aharonian et al. 2006a; Albert et al. 2008). ** Theoretical Models for EBL: **# Backward evolution model: Malkan & Stecker 1998; Totani & Takeuchi 2002; Stecker et al. 2006; Franceschini et al. 2008 **# Forward evolution model: Kneiske et al. 2004; Finke et al. 2010 **# Semi-analytical Models of Hierarchical Galaxy Formation * The EBL in the X-ray, or cosmic X-ray background (CXB), is now known to be the relic emission of cosmic supermassive black hole (SMBH) accretion (e.g. Comastri et al. 1995) arXiv:1212.3642 Really High-Redshift Universe * Molecular hydrogen has been invoked as a signiﬁcant coolant of primordial gas leading to the formation of ﬁrst stars and galaxies (e.g. Haiman 1999; Bromm & Larson 2004; Glover 2005; Glover 2012 ) arXiv:1212.2964 Galaxies in Really High-Redshift * There is now overall evidence for the mass build-up of early galaxies at z~4-8 based on the evolution of the cosmic star-formation density (Giavalisco et al. 2004, Bouwens et al. 2004, 2007, Bunker et al. 2004, McLure et al. 2006, 2009, Yan et al. 2006, 2010, Castellano et al. 2010, Oesch et al. 2010b) arXiv:1212.1448 * A wider variety of results have been obtained on the ultraviolet spectral slopes and stellar populations of these early star-forming galaxies at z~7-8 (Bouwens et al. 2009, 2010, 2012, Ono et al. 2010, Bunker et al. 2010, Finkelstein et al. 2010, 2012b,a, Yan et al. 2011b,a, McLure et al. 2010, 2011, Grazian et al. 2011, 2012, Bradley et al. 2012, Dunlop et al. 2012a,b) arXiv:1212.1448 Reionization * About the calculation of escape fraction in high-z galaxies, see Benson et al. 2012 * The Gunn–Peterson test, in which a non-trivial ion fraction creates a trough by line absorption at every redshift (Gunn & Peterson 1965), is the most direct test of the later stages of helium reionization. arXiv:1212.1502 * Existing cosmological observations show that the reionization history of the universe at z > 6 is likely both complex and inhomogeneous (e.g. Haiman 2003; Choudhury & Ferrara 2006; Zaroubi 2012 ) ** When does the reionization started: from the polarization signal of the CMB anisotropy power spectrum, the total optical depth to electron scattering suggest it started around z_{ri}=11 ( Komatsu et al. 2011 ) * Other possible probes: *# 21-cm HI spin-flip line: Madau et al. 1997; Loeb & Zaldarriaga 2004; Santos et al. 2005; Santos & Cooray 2006; McQuinn et al. 2006; Bowman et al. 2007; Mao et al. 2008 *# Line emission associated with atomic and molecular: *## CO: Gong et al. 2011 *## CII: Gong et al. 2012a *## Lyman-alpha: Silva et al. 2012 *## H_2: Gong et al. 2012b (astro-ph:1212.2964) ** More sensitive to the late stages of reionization (Righi et al. 2008; Visbal & Loeb 2010; Carilli 2011; Lidz et al. 2011 ) * The reionization epoch of singly ionized helium (He II) is believed to start at redshifts z~3.5–4 and be nearly complete by z≃2.7 (Furlanetto & Oh 2008) ** delayed because of the need for high-energy photons than stars provide (E>4 ryd) ** This is consistent with redshift estimates from the intergalactic medium (IGM) temperature (e.g., Becker et al. 2011), which increases noticeably during helium reionization, as well as estimates from the redshift evolution of the He II Gunn–Peterson optical depth (e.g., Syphers et al. 2011a, 2012; Worseck et al. 2011; but see Davies & Furlanetto 2012) arXiv:1212.1502 Population III * The high Jeans mass of metal-free gas suggests a top-heavy IMF (Abel et al. 2000; Bromm et al. 1999; Abel et al. 2002; Yoshida et al. 2003) for Population III stars (Pop-III) arXiv:1212.1157 * Pop-III stars may lead to the occurrence of pair instability supernovae (PISNe) (Heger & Woosley 2002) arXiv:1212.1157 HST Deep Fields * Hubble Deep Field (Williams et al. 1996) * Hubble Deep Field South (Casertano et al. 2000; Williams et al. 2000; Lucas et al. 2003) * Ultra-Deep Field (Beckwith et al. 2006; Thompson et al. 2005) ** Following programs in 2005, PI.: M. Stiavelli, see Oesch et al. 2007; 2009 ** WFC3/IR follow-up in 2009, PI.: G. Illingworth, see Oesch et al. 2010a,b; Bouwens et al. 2011b ** UDF12, PI.: R. Ellis, see Ellis et al. 2012; Koekemoer et al. 2012 Other Shallower HST Surveys * GOODS: (Giavalisco et al. 2004) * '''GEMS' : (Rix et al. 2004) * '''AEGIS': (Davis et al. 2007) * '''COSMOS': (Scoville et al. 2007; Koekemoer et al. 2007) * WFC3 ERS: (Windhorst et al. 2011) * CANDELS (Grogin et al. 2011; Koekemoer et al. 2011) * BoRG: (Trenti et al. 2011) * HIPPIES: (Yan et al. 2011b) * CLASH: (Postman et al. 2012) The Large-Scale Structure and Cosmology Clustering of Galaxies * First statistical studies of galaxy clustering: (Totsuji & Kihara 1969; Peebles 1973; Hauser & Peebles 1973, 1974; Peebles 1974 ) found the galaxy correlation function behaves like a power law, which is difficult to explain from first principle (Berlind & Weinberg 2001 ) ** Recent studies found deviations from a power law (Zehavi et al. 2005a),, and the deviation can be explained by a 3-parameter Halo Occupation Distribution model (e.g. Jing, Mo & Borner 1998; Ma & Fry 2000; Peacock & Smith 2000; Seljak 2000; Scoccimarro et al. 2001; Berlind & Weinberg 2001; Cooray & Sheth 2002 ) ** This deviation (a dip in the Correlation Function at 1-3 h^{-1} Mpc) can be explained by the transition from the 1-halo to 2-halo term in the HOD model. ** The deviation is larger for highly clustered bright galaxies (Zehavi et al. 2005a,b; Blake, Collister & Lahav 2008; Zheng et al. 2009; Zehavi et al. 2010 ), and at high redshift (Conroy, Wechsler & Kravtsov 2006 ), which agrees with theoretical predictions (Watson et al. 2011 ). arXiv:1212.3610 * HOD modelling has been applying to galaxy clustering data from : *# 2dFGRS: (Porciani, Magliocchetti & Norberg 2007; Tinker et al. 2006 ) *# SDSS : (van den Bosch, Yang & Mo 2003; Magliocchetti & Porciani 2003; Zehavi et al. 2005a,b; Tinker et al. 2005; Yang et al. 2005, 2008; Zehavi et al. 2010 ) *# VVDS (Abbas et al. 2010); Bootes (Brown et al. 2008); DEEP2 (Coil et al. 2006); LBGs in GOODS (Lee et al. 2006) * The measurements of the cosmological parameters heavily rely on accurate measurements of power spectra. Power spectra describe the spatial distribution of an isotropic random ﬁeld, deﬁned as the Fourier transform of the spatial correlation function. arXiv:1212.3194 * The dependence of galaxy clustering on galaxy properties has been observed in numerous galaxy surveys (e.g., Davis & Geller 1976; Davis et al. 1988; Hamilton 1988; Loveday et al. 1995; Benoist et al. 1996; Guzzo et al. 1997; Norberg et al. 2001, 2002; Zehavi et al. 2002, 2005b, 2011; Budav´ari et al. 2003; Madgwick et al. 2003; Li et al. 2006; Coil et al. 2006, 2008; Meneux et al. 2006, 2008; Wake et al. 2008; Swanson et al. 2008; Meneux et al. 2009; Ross & Brunner 2009; Skibba et al. 2009; Loh et al. 2010; Ross et al. 2010, 2011a; Wake et al. 2011; Christodoulou et al. 2012; Mostek et al. 2012) arXiv:1212.1211 * The subhalo abundance matching (SHAM) method makes use of subhalos in high resolution N-body simulations and connects them to galaxies to interpret galaxy clustering (see, e.g., Kravtsov et al. 2004; Conroy et al. 2006; Guo et al. 2010; Nuza et al. 2012). arXiv:1212.1211 * The halo occupation distribution (HOD) framework (see e.g., Peacock & Smith 2000; Seljak 2000; Scoccimarro et al. 2001; Berlind & Weinberg 2002; Berlind et al. 2003; Zheng et al. 2005) or the closely related conditional luminosity function (CLF) method (Yang et al. 2003, 2005) describe the number of galaxies as a function of halo mass, and galaxy clustering is used to constrain the HOD or CLF parameters. arXiv:1212.1211 Weak Lensing * Weak gravitational lensing by large-scale structure provides valuable cosmological information, especially since weak lensing is sensitive to the distance-redshift relation and the time-dependent growth of structure, it is a particularly useful tool for constraining models of dark matter. (Bartelmann & Schneider 2001; Albrecht et al., 2006; Peacock et al., 2006; Albrecht et al., 2009 ) ** To constrain the dark energy, lensing signal must be measured at several redshifts--the so called weak lensing tomography (Hu 1999; Huterer 2002; Bacon et al. 2005; Semboloni et al. 2006; Massey et al. 2007; Schrabback et al. 2010 ) Simulation of Galaxy Formation Tidal Stripping and Merging * When dark matter haloes merge, these protogalaxies also merge; depending on the mass ratio the satellite galaxy can either rapidly merge with the central object or orbit around it for a consistent amount of time (e.g., Chandrasekhar 1943; Binney & Tremain 2008; Jiang et al. 2008; Boylan-Kolchin et al. 2008 ) ** About the possible progressive mass loss, both in dark matter and stellar component (e.g. Mayer et al. 2001a; Klimentowski et al. 2007; Penarrubia et al. 2008; Kazantzidis et al. 2011 ) ** N-body simulations about this topic: (Moore et al. 1999; Gnedin 2003; Mastropietro et al. 2005; Mayer et al. 2001a, b; Klimentowski et al. 2009a; Kazantzidis et al. 2011; Villalobos et al. 2012; Chang et al. 2012 ) arXiv:1212.3408 * Environmental effects (e.g. tides and stripping) have an important role in shaping the properties of the local dwarf spheroidal galaxies (e.g., Einasto et al. 1974; Faber & Lin 1983; Mayer et al. 2001a, 2001b; Kravtsov et al. 2004; Mayer et al. 2006, 2007; Klimentowski et al. 2007; Penarrubia et al. 2008; Klimentowski et al. 2009a, 2009b ) * Using this new MHD code (+AREPO), we simulate the formation of isolated disk galaxies similar to the Milky Way using idealized initial conditions with and without magnetic fields. We found that the magnetic field strength is quickly amplified in the initial central starburst and the differential rotation of the forming disk, eventually reaching a saturation value. At this point, the magnetic field pressure in the interstellar medium becomes comparable to the thermal pressure, and a further eficient growth of the magnetic field strength is prevented. The additional pressure component leads to a lower star formation rate at late times compared to simulations without magnetic fields, and induces changes in the spiral arm structures of the gas disk. arXiv:1212.1452